Some sticks are illegal when you get them (maybe Thornton?) but most are not. It's only when you get out the old heat gun that you would have a problem. I know for a fact that about 20% of my league uses deep curves, but who really cares? The only real advantage is toe-dragging someone. When it comes to roofing a shot from close quarters you don't need that curve to do it. It also pretty much nullifies a good slap shot, not that it's important to have one to score.